One more hybrid graphics Linux method: Asus K52Jc

The Asus K52Jc laptop DSDT contains a method called:

\_SB.PCI0.PEG1.GFX0.DOFF

You can quite possibly use the lenovo_acpi module and substitute the default method for the one in your DSDT:

http://github.com/doudou/lenovo_acpi